Аннотация:Trichinellosis is a natural focal disease that is registered universally. Data are available on different virulences among T. nativa strains in relation to some species of mammals. The variability of host-parasite relationships in trichinellosis largely depends on the qualitative and quantitative composition of protein molecules present in the excretory-secretory (E-S) products of Trichinella. Larvae of T. nativa strain MK032473 (originally isolated from Ursus arctos muscles) were passaged on white mongrel mice. The biomass of invasive larvae was isolated from the muscle tissues of experimental animals by proteolysis in artificial gastric juice, and then cultured in DMEM. E-S products, collected at 24 h, 48 h and 72 h of cultivation were analysed by liquid chromatography tandem mass spectrometry (LS-MS/MS). Diverse functional proteins were revealed in E-S products at each stage of cultivation: more than 100 at 24 h, more than 170 at 48 h and more than 250 at 72 h of cultivation. Our results show that the protein composition in E-S products of T. nativa changes depending on the prolongation of cultivation. Common proteins, previously found by us in E-S products of T. spiralis and T. pseudospiralis (Odoevskaya et al., 2018), namely deoxyribonuclease family proteins, 5’-nucleotidases and serine proteases were revealed at all three stages of T. nativa larvae cultivation. A comparison of the E-S protein spectrum revealed in T. nativa with that of T. spiralis and T. pseudospiralis studied by us earlier allows measuring the extent of similarity of E-S products in these species.